Two-part excavating tool

ABSTRACT

Attaching means for releasably attaching two excavator tool parts, one tool part having a nose portion and the other having a socket for receiving that nose portion. The attaching means including at least one pair of angularly disposed side locking surfaces formed on the nose portion, and a complementary pair of such surfaces formed in the socket, which frictionally engage to hold the two tool parts in assembly. At least one side surface of at least one of the tool parts being contoured to provide restraining means such as to substantially prevent relative lateral movement between the nose portion and the socket when the tool parts are assembled.

United States Patent [1 1 Cullen May 6,1975

1 1 TWO-PART EXCAVATING TOOL [75] Inventor: Clifford Cullen, Doncaster,

Victoria, Australia [73] Assignee: Vickers Ruwolt Proprietary Limited,

Richmond, Victoria, Australia {22] Filed: July 11, 1973 [21] Appl. No:378,147

Related U.S. Application Data [63] Continuation of Ser. No. 70,396,Sept, 8, 1970,

abandoned.

[30] Foreign Application Priority Data Sept. 9, 1969 Australia 60633/69[52] US. Cl. 37/142 R; 172/749 [51] int. Cl E021 9/28 [58] Field ofSearch 37/142 R, 142 A, 141 R, 37/141 T; 172/713, 749; 175/412; 408/231,232, 713

[56] References Cited UNITED STATES PATENTS 1,262,870 4/1918 Thomson37/142 R 2,040,085 5/1936 Fykse et a1. 2,050,014 3/1936 Morrison 37/142R 2,397,521 4/1946 Askue 37/142 R 2,752,702 7/1956 Nelson 37/142 R3,012,346 12/1961 Larsen 37/142 A 3,073,502 1/1963 Delli-Gatti, Jr.37/142 R 3,117,386 1/1964 Ferwerda 37/142 R 3,496.658 2/1970 Eyolfson37/142 R 3,623,247 1/1970 Stepe 37/142 R FOREIGN PATENTS OR APPLlCATlONS1,175,713 12/1969 United Kingdom,.,......, 37/142 R PrimaryExaminerEdgar S. Burr Assistant Examiner-E. H. Eickholt Attorney, Agent,or FirmDiller, Brown, Ramik & Wight [57] ABSTRACT Attaching means forreleasably attaching two excavator tool parts, one tool part having anose portion and the other having a socket for receiving that nose portion. The attaching means including at least one pair of angularlydisposed side locking surfaces formed on the nose portion, and acomplementary pair of such surfaces formed in the socket, whichfrictionally engage to hold the two tool parts in assembly. At least oneside surface of at least one of the tool parts being contoured toprovide restraining means such as to substantially prevent relativelateral movement between the nose portion and the socket when the toolparts are assembled.

16 Claims, 24 Drawing Figures PATENIEBHAY ems 3.881.262

sum 2 EF 6 26 a: 1.9270 2: 2a 11 a 2 /6 9 11 r I 28 MM ms 1%. Z

M/VENTUR CLIFFORD CULLEN PATENTEB W 5 I975 SHEET 3 BF 6 II I INVENTDRCLIPF'URD CULLEN OQ AJJA ATTO RN EIS PATENTEUHAY 61.975 3,881,262

SHEET UF 6 M/VENTURS CL\PFDRD CULLEM ilw "QTT D QM EYs TWO-PARTEXCAVATING TOOL This is a continuation application of application Ser.No. 70,396, filed Sept. 8, 1970 and now abandoned.

This invention relates to means for releasably attaching parts of anexcavator device in assembly, and is particularly although notexclusively applicable to two part excavating tools of the kindincluding an adaptor and a removable point or tooth element. That is, inone form, the invention provides means for releasably retaining thosetwo parts in assembly. The invention is also applicable to attachingprotective shrouds to the front edge of a scraper blade or digger bucketbase, but it will be convenient to mainly describe the invention inrelation to digger teeth.

Two-part excavating tools of the kind indicated are desirable because oftheir facility to enable replacement of the tooth element, which is ofcourse subjected to the greater wear during use. Difficulty has beenexperienced however, in providing effective and convenient releasableretaining means for connecting the two parts of such tools. Numerousconstructions have been proposed, bit they generally suffer fromcomplexity and/or difficulty of releasing, and in some cases they areonly partially effective.

Reference throughout the specification to excavators or excavatingequipment is to be understood as embracing all types of earth handlingand mineral processing equipment such as scrapers, diggers, dredges(whether for open-cut mining or underwater dredging), earth boringequipment, and tractor mounted buckets, rippers, scraper blades and thelike. The invention is particularly applicable to components ofexcavating equipment which are subjected to a high rate of wear andheavy loading during use, and must be adapted for convenient removal forreplacement or repair.

It is a principal object of the present invention to provide improvedretention means for excavator devices, and such means which isapplicable to a two-part excavating tool. It is a further object of theinvention to provide a tool adaptor and/or tooth elemet having suchretention means.

It is a still further object of the invention to provide a shroudelement having retention means such as to allow ready releasableattachment to an excavator plate member.

Yet another object of the invention is to provide an excavator tool parthaving retention means such as to not require separate elements such aspins, wedges or bolts to effect secure and releasable attachment toanother tool part, but which retention is effected solely throughfrictional engagement between surfaces having a Morse or similar taper,which is preferably within the region of :l. A further object of theinvention is to provide an excavator tool part having such retentionmeans, and also having restraining means which functions to preventsubstantial lateral movement between the two tool parts when assembled.

Still a further object of the invention is to provide a two-partexcavator tool combination in which the two parts are releasablyretained in secure assembly without the aid of separate elements such aspins, wedges, or bolts, but which retention is effected solely byfrictional engagement between surfaces having a Morse or similar taper,which is preferably within the region of 20: I. Another object of theinvention is to provide such a combination in which restraining meansfunctions to LII prevent substantial lateral movement between the twoparts of the assembly.

Another object of the invention is to provide an com bination asaforesaid having the desired retaining and restraining means formed onside surfaces of a nose portion of one tool part, and substantiallycomplemew tary side surfaces of a socket of the other tool part whichreceives the nose portion, which side surfaces are tapered andfrictionally engage to retain the two parts in assembly. It is yetanother object of the invention to form the two parts of the combinationso that the nose portion is able to move deeper into the socket as wearoccurs between engaging surfaces of those members.

The following description refers in more detail to those essentialfeatures and further optional featurs of the invention. To facilitate anunderstanding of the in vention, reference is made to the accompanyingdraw ings where these features are illustrated in preferred form. It isto be understood however. that the essential and optional features ofthe invention are not limited to the specific forms of these features asshown in the drawings.

In the drawings:

FIG. 1 is a side elevational view of one embodiment of the invention,and which is partially sectioned for convenience of illustration;

FIG. 2 is a partsectioned plan view of the embodi ment shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken along line lII-lll ofFIG. 1;

FIG. 4 is a view similar to FIG. 3, but showing an alternative rib andflute arrangement;

FIG. 5 is an end view of the tooth element ofthe em bodiment of FIG. I;

FIG. 6 is an end view of the adaptor of the embodiment of FIG. 1;

FIG. 7 is an end view of a modified form of the tooth element of FIG. I;

FIG. 8 is an end view of an adaptor for use with the tooth elementaccording to FIG. 7;

FIG. 9 is a view similar to FIG. I, but showing another embodiment ofthe invention;

FIG. 10 is a part-sectioned plan view of the embodiment of FIG. 9;

FIG. 11 is a transverse cross-sectional view taken along line XI-XI ofFIG. 10;

FIG. I2 is a view similar to FIG. Ii but showing a modified form of theFIG. I0 embodiment;

FIG. 13 is a view similar to FIG. II, but showing yet anothermodification;

FIG. 14 shows still another variation of the construction shown in FIG.II,

FIG. [5 is yet a further modification of the FIG. 11 construction;

FIG. 16 is another possible modification of the FIG. 11 construction;

FIG. 17 is a view similar to FIG. II, but showing an embodiment in whichthe nose portion of the adaptor is not split into two sections;

FIG. 18 shows a modification of the arrangement shown in FIG. I7;

FIG. 19 is a longitudinal sectional view of a further embodiment of theinvention including a plate member and shroud element;

FIG. 20 is a sectioned plan view of the construction shown in FIG. I9;

FIG. 2I is a plan view showing a tooth adaptor and shroud elementmounted side by side on a plate member;

FIG. 22 is a transverse cross-sectional view taken along line XXIlXXlIof FIG. I9;

FIG. 23 is a longitudinal cross-sectional view of a modification of theFIG. 19 embodiment; and

FIG. 24 is a transverse cross-sectional view taken along line XXIVXXIVof FIG. 23.

A typical tooth adaptor 2 to which the invention is applicable includesa body portion 3 having a mounting shank 4 extending from a rear sidethereof and a nose 5 extending from its front side. The shank 4 and nose5 extend in opposite directions. and may be in substantial alignment ifthe nose is formed as a single section. but it is preferred to have thenose formed of two sections 5a and 5b separated longitudinally by a gap7. Generally. the shank 4 is substantially square or rectan gular intransverse cross-section. although it may be of any other suitableshape. The shank 4 is usually provided with a slot 6 or other apertureto enable the adaptor 2 to be mounted on an excavating device (notshown) such as a bucket or blade.

For convenience. the adaptor 2 will be hereinafter described as having aparticular disposition. but it may be mounted on an excavating device soas to have any other desired disposition. Thus. relative terms such as"upper" and "lower". and words of similar import, as used throughoutthis specification are not to be taken as limiting on the invention.

Each section of the adaptor nose 5 is preferably substantially square orrectangular in transverse crosssection and has upper and lower surfacesand two oppositc side surfaces. The upper and lower surfaces convergeaway from the adaptor body 3, and it is preferred that the side surfacesconverge in a like manner.

In the embodiment of Hg. 1, at least the upper or lower surface of thenose 5 forms part of the locking means for releasably holding theadaptor 2 in assembly with a tooth element 8. and is contoured so as toincrease its area for a reason hereinafter made clear. That contouringmay take the form of at least one flute or groove 9 formed in thesurface and extending generaily in the direction of the adaptor nose 5.It is preferred however. that both the upper and lower surfaces arecontoured. and it is further preferred that the side surfaces of thenose 5 also form part of the locking means as hereinafter described.

In accordance with the embodiment of FIG. I, a plurality of flutes 9 areformed in each of the upper and lower surfaces of the nose 5, and theflutes 9 in each surface extend substantially parallel to each other. Arib II is of course defined between each two adjacent flutes 9, and theopposite side faces 12(see FIGS. 3 and 4) ofeach flute 9 preferablyslope upwardly away from each other. The slope of each of the side facesI2 may be in the range l5-"5, and is preferably approximately so thatthe included angle 'A' (see FIG. 3) formed between adjacent faces 12 isapproximately 40 in the preferred arrangement. The base of each flute 9and the land or apex surface of each rib may be substantially flat,although they may be curved if desired and the arrangement is preferablysuch that a clearance 13 (see FIGS. 3 and 4) remains between the base ofeach flute 9 and the apex of an associated rib of the tooth element 8,when the two tool parts are assembled. It is also preferred that thedepth of each flute 9 is substantially the same as its greatest widthi.e.. the width at the top of the flute 9.

The two surfaces of the nose 5 in which the flutes 9 are formed mayslope at an angle within the range l6-20 and preferably at an angle ofapproximately 18, so that the included angle B (see FIG. I between theupper and lower surfaces of the nose 5 is approximately 36 in thepreferred embodiment. .It is not necessary however, that the upper andlower surfaces have the same slope, but it is generally convenient toform such a symmetrical arrangement. The slope of each of the four sidesurfaces of the nose 5 i.e.. two outer surfaces 14 and two innersurfaces [5 may be in the range 25, and is preferably approximately 3 or4 so that the included angle C (see FIG. 2) defined between any twoadjacent side surfaces is approximately 6-8 in the preferred embodiment.As for the upper and lower surfaces, the slope of the side surfaces neednot be the same.

A modified form of the above described adaptor 2 is shown in FIG. 8, andin that modification, the flutes 9 and ribs II are of substantiallyarcuate form in transverse cross-section so as to produce a wave orcorrugated form in transverse cross-section. In such an ar rangement theflutes 9 may be relatively shallow compared to their width. and thewidth of each rib II is preferably less than that of each flute 9.

In either ofthe foregoing embodiments, an outwardly stepped section maybe formed on each side surface of the nose 5 so as to define upper andlower locking shoulders I6 and I7 respectively (see FIGS. 6 and 8) whichmay slope at an angle of between 2(i. but pref erably 4", so as toconverge away from the adaptor body 3. It is also preferred that theslope of each of the shoulders 16 and 17 increases at the front endportion thereof to facilitate location of the tooth element 8 on theadaptor 2.

The tooth element 8 may have the usual blade section 18 and enlargedbody portion I9 which includes a socket 21 for receiving the adaptornose 5. The socket is preferably substantially complementary in shape tothe adaptor nose 5 so that in the assembled condition of the two toolparts there is a satisfactory degree of surface contact between the nose5 and socket 2|. Preferably however. the nose 5 and socket 21 aredimensioned so that the nose 5 does not bottom within the socket 21, anda space 22 always remains between adjacent end faces of the nose 5 andsocket 21, and a similar space 23 remains between the adjacent end facesof the respective body portions 3 and 19 (see FIG. 1).

For a two section adaptor nose 5 as in the embodi ments so fardescribed. it is preferred that the socket 21 is also divided into twosections 210 and 21b by a tongue member 24. A strong connection isachieved by forming the tongue member 24 integral with the upper andlower walls of the socket 21. The socket sections 210 and 21b haveflutes 25 formed in the upper and lower surfaces thereof to correspondwith the ribs II of the adaptor nose 5, and a rib 26 is defined betweeneach two adjacent flutes 25 so as to locate within a respective flute 9of the adaptor 2. Furthermore, the fluted surfaces of the socket Zlpreferably slope at sub' stantially the same angle as the correspondingsurfaces of the adaptor nose 5.

It is also preferred that the inner and outer side surfaces 27 and 28respectively of the socket 21, slope at substantially the same angle asthe corresponding side surfaces of the adaptor nose 5. Thus, the cavity21 and nose 5 are of substantially complementary shape, except for theclearances previously mentioned, and a further clearance 29 preferablyprovided between the base of each flute 25 and the associated rib 11(see FIGS. 3 and 4). The tooth elements 8 of FIGS. 5 and 7 areconstructed to cooperate with the adaptors of FIGS. 6 and 8respectively, and the flutes 25 of each tooth element 8 have atransverse cross-sectional shape substantially complementary to that ofthe ribs 11 of the respective adaptor 2.

It will be appreciated that with the foregoing arrangement, the toothelement 8 may be firmly retained on the adaptor 2 purely by frictionalengagement, and separation of the two parts is relatively simple. Forexample, the parts may be separated by driving a wedge or the likebetween the adjacent end faces of the two body portions 3 and 19. Also,in use, the loading on such a tool is usually such that the toothelement 8 is urged more firmly on to the nose 5 of the adaptor 2.

Because of the high pressure existing in practice between the engagingsurfaces of the nose 5 and socket 21, the increased area of thosesurfaces increases the frictional resistance to sliding. In addition,there is a wedging action between the ribs and flutes which also aids tothe retention effect of the constructions described.

It will be obvious that the outer side surfaces of the adaptor nose 5and tooth element socket 21 may be fluted in substantially the samemanner as described for the upper and lower surfaces thereof. Similarlyfor the inner side surfaces of those tool parts. Thus, either or bothpair of side surfaces may be fluted additional or alternative to flutingthe upper and lower surfaces.

It has been found that the fluted surfaces of the nose 5 and socket 21need not engage to achieve adequate locking power between the toothelement 8 and adaptor 2. That is, clearance 31 may be provided at thesides of each rib I1 and 26 as shown in FIG. 4, and the locking means isdefined by frictionally engaging side sur faces of the nose 5 and socket21. In fact, suitable retention is obtained with only one pair of sidesurfaces engaging i.e., surfaces engaging surfaces 27, or surfaces 14engaging surfaces 28.

The clearance spaces 13, 22, 23, 29 and 31 (when provided) enable thenose 5 to move deeper into the socket 21 as wear takes place betweenengaging surfaces of the two tool parts. Thus, the useful life of theassembly is extended.

In both the FIGS. 3 and 4 arrangements, the cooperating flutes and ribsdefine restraining means which prevents substantial lateral movement ofthe nose 5 relative to the socket 21. Although the clearance 31 wouldseem to allow such movement in the FIG. 4 arrangement, the slope of thefluted surfaces is such that in practice, relatively little lateralmovement is permitted before surface engagement occurs at the upper orlower fluted surfaces. It is to be understood that the arrangements ofFIGS. 3 and 4, although shown in relation to the FIGS. 5 and 7embodiment, are equally applicable to the FIGS. 6 and 8 embodiment.

FIGS. 9 and 10 show a further embodiment of the in vention which makesuse of the fact that side surface engagement alone provides adequatelocking between the two tool parts. For convenience of description,components of this embodiment which correspond to components of theFIGS. 1 and 2 embodiment, will be given the same reference numeralsexcept that those numerals will form part of the series 101 to 200instead of the series I to I00.

Basically, the FIG. 9 embodiment is substantially the same as that ofFIG. 1, except for the omission of flutes in the upper and lowersurfaces of the nose and cooperating socket 121 of the tooth element108. The nose 105 is slightly different in that the upper and lowersurfaces thereof are substantially parallel adjacent the body portion103 and converge from that parallel section at an included angle B whichmay be in the range 20 to 40 inclusive, but is preferably approximately30. The angle C of the side locking surfaces 114 and of the nose 105 ispreferably substantially the same as for the previously describedembodiment, and the side locking surfaces 127 and 128 of the socket 121slope accordingly. The upper and lower surfaces of the socket 121 arepreferably arranged substantially complementary to the correspondingsurfaces of the adap tor nose 105, but with clearance 113 providedtherebetween.

The locking means in this embodiment is constituted solely by the sidesurfaces 114 and 115 of the adaptor nose 10S engaging corresponding sidesurfaces 128 and 127 respectively of the socket 121 as shown in FIG. 11.The clearance 113 is provided at the top and bottom surfaces of each ofthe nose portion sections to allow the nose portion 105 to move deeperinto the socket 121 to compensate for wear. Although both pairs of sidesurfaces are shown engaging in FIG. 11, it has been found thatsatisfactory retention is achieved with the surfaces 115 and 127 onlyengaging as shown in FIG. 13 or surfaces 114 and 128 only engaging asshown in FIG. 14. That is. FIGS. 13 and I4 show alternative arrangementsof the construction according to FIGS. 9 to II.

The restraining means of the FIGS. 9 to II embodiment is preferablydefined by contouring of at least one pair of the side locking surfaces.That is, one pair of side surfaces of either the nose portion I05 or thesocket 121 may be contoured, but it is preferred that corresponding sidesurfaces of both tool parts are contoured. In the arrangement accordingto FIG. II, the surfaces 115 and 127 have substantially complementarycontours, and although the surfaces 115 and 127 are shown as convex andconcave respectively, the reverse may obviously apply. The contouredsurfaces may be part cylindrical, and are preferably formed with aradius at least equal to the maximum width of the nose portion 105.

Contouring as shown of course restrains the adaptor nose 105 againstsubstantial lateral movement towards and away from the upper and lowersurfaces of the socket 121, and consequently takes the beam loading onthe tooth element 108 during use. It will be clear that other forms ofcontouring may be used to achieve the same purpose, but a curvedarrangement as shown is generally found convenient to manufacture.

The modified arrangements shown in FIG. 13 and 14 are contouredsubstantially as described above, but are distinguished from the FIG. 11arrangement in that clearance is provided at the outer and inner sidesurfaces respectively.

A further modification of the FIG. 11 arrangement is shown in FIG. 12,and in that modification the contoured side surfaces 115 have a greaterradius than the adjacent contoured surfaces [27. This difference inradii ensures that the surfaces IIS and I27 will not bear at the centreonly. which would possibly permit some undesirable lateral movement ofthe nose portion I05. The contoured surfaces of the arrangements shownin FIG. 13 and I4 may of course be provided with different radii toachieve the same effect.

FIG. I shows another way in which proper hearing may be achieved betweencontoured surfaces of the adaptor nose I05 and the socket I21. For thepurpose of illustration. this modification is shown in relation to theFiG. I3 arrangement, but it is equally applicable to the arrangement ofFIGS. II and [4. According to this modification. a fiat 132 is providedin the central region of each surface Hi to provide a clearance with therespective adjacent surface I27.

Still further. ribs Ill and 126 may be formed on the upper and lowersurfaces of the adaptor nose I05 and the socket [21 respectively as isshown in FIG. I6, so as to form a further part of the loading means. andagain that variation may be applied to any of the arrangements of FIGS.II to I5. If clearance is provided between the ribs III and [26 as shownin FIG. 4, they will not function as part of the locking means. but willnevertheless serve as additional restraining means.

FIGS. 17 and 18 show possible arrangements in which the nose portion 105is not split longitudinally as previously described. It will beappreciated however. that any of the surface arrangements described fora two piece nose portion 105 will be equally applicable to asingle-piece nose portion as shown in FIGS. 17 and I8. FIG. 17 shows anarrangement in which the contoured surfaces are the locking surfaces.whereas in FIG. 18 the side locking surfaces are substantially flat andadjacent upper and lower surfaces 133 and 134 of the adaptor nose I05and socket I21 respectively. are contoured but are provided withdifferent radii to form clearance H3. Thus. in the FIG. 18 arrangement.the surfaces 133 and 134 bear along the side regions only to form therestraining means. whilst forming clearance H3 in the centre region topermit the adaptor nose 105 to move deeper into the socket 121 tocompensate for wear. The same effect could be achieved with a flat oneach surface 133, and the contours formed with the same radius.

Yet another embodiment of the invention is shown in FIGS. 19 to 22, andin this embodiment the attaching means of the invention is applied to ashroud element 235 for protecting an edge portion of a plate member 236which may define a scraper blade. the base of a digger bucket. or anysimilar excavator device. Components of this embodiment which correspondto components of the first described embodiment will be designated bylike reference numerals except that they will form part of the series20I to 300.

Preferably. the body portion 203 of the shroud 235 has a cavity 237defined therein which receives an edge portion ofthe plate member 236 asis shown in FIG. 19. A nose portion 205 extends rearweardly from thebase of the cavity 237 to locate within the socket 221 formed in thefront edge surface of the plate member 236. and that nose and cavity mayhave cooperating and adjacent surfaces according to any of thearrangements previously described. Also. the nose portion may be formedof a single section rather than two sections as shown in FIG. 20. Forconvenience however. the nose 205 and cavity 221 are shown to bearranged substantially as in the embodiment of FIG. I], and FIG. 22shows that arrangement as applied to the shroud element 235 and platemember 236.

A recess 238 is preferably provided in both the upper and lower surfacesof the plate member 236 to contain skirt sections 239 of the shroudelement 235. In addi tion. a slot 24! may be provided in the platemember 236 to permit a wedge to be driven. or a lever to be manipulated, between that member and the shroud elment 235 to effectseparation ofthose tool parts. In all other respects. this embodiment isconstructed and adapted to function substantially as described inrelation to the previous embodiments.

Shroud elements 235 are often mounted between tooth adaptors of the kindpreviously described. and section of a typical assembly is shown in planview in FIG. 21. The adaptor 242 is different to those previouslydescribed only in that a mounting shank is not provided. but the bodyportion of the adaptor fits over the plate member 236 and is securedthereto in a known manner by a key 243 and locking wedge 244.

An alternative form of the FIG. 19 to 22 embodiment is shown in FIGS. 23and 24, and in this modification the cavity 221 is open at its lowerside and a resilient pad 245 is located between the plae member 236 andthe upper skirt section 239 of the shroud element 235. The pad 245 maybe secured by adhesive or other means to either the shroud element 235or to the plate member 236, and separation of the two tool parts can beeffected by driving a wedge or manipulating a lever within the space 246provided between the lower skirt section 239 and the tongue member 224.Again the surfaces of the nose portion 205 and the socket 221 can beformed in accordance with any of the arrangements previously desscribed.

It will be appreciated that the foregoing embodiments and arrangementsrepresent a very small portion only of the possible applications andforms of the invention. The invention presents a major advance inattaching means for replaceable components of excava tor equipment.because of its relative simplicity and reliability in service.Manufacturers of excavating equipment have long striven to solve theproblems overcome by the present invention. and prior attaching means ofthe kind in question have generally been complex and- /or inefficient inoperation. Actual field tests have shown the attaching means of theinvention to have far superior holding power than prior arrangements.even without full contact between adjacent locking surfaces.

A person skilled in the art will readily understand that the variousangles referred to may be determined according to the particularmaterials employed to form the tool parts. Consequently. the anglesspecified herein are to be taken as examples only for parts of forgedsteel or similar metal. Furthermore, in all embodiments described. therelative positions of the coop erating nose and socket may be reversed.That is. the socket may be provided in the adaptor or shroud element. inwhich case the nose will be formed on the tooth element or plate memberrespectively.

Finally. it is to be also understood that various alterations.modifications and/or additions may be introduced in the preferredconstructions and arrangement of parts previously described withoutdeparting from the spirit or ambit of the invention.

I claim:

1. An excavator tool part adapted for weding engagement with anothertool and having a motor external load bearing surface and a socketincluding locking side surfaces which extend transverse to said majorload bearing surface, said locking side surfaces facing in oppositedirections, being non-parallel in the direction of engagement with saidanother tool part and being curved in opposite directions in transversecross section, at least at their edges, and non-locking socket sidesurfaces extending transverse to said locking surfaces, said non-lockingsurfaces facing in opposite directions and being non-parallel in thedirection of engagement with said another tool part, and the includedangle between said non-locking surfaces is greater than the includedangle between said locking surfaces.

2.. A tool part as defined in claim 1 wherein, the included anglebetween said locking surfaces is in the range 2 to 8 inclusive.

3. A tool part according to claim 2 wherein the included angle betweensaid non-locking surfaces is in the range to 40 inclusive.

4. An excavator tool including two parts held in releasable combination;one part being subjected to wear in use and being replaceable, andhaving a major external load bearing surface; one said part having asocket. the second part having a nose, said parts being held incombination by frictional wedging engagement of said socket and nose byrespective locking surfaces, all of which extend transverse to saidmajor load bearing sur face; each part having at least one pair of saidlocking surfaces and at least one pair of non-locking surfaces whichextend transverse to said locking surfaces, the surfaces of each pairface in opposite directions and are non-parallel in the direction ofengagement between said parts; the included angle defined between eachpair of locking surfaces being less than the included angle definedbetween each pair of non-locking surfaces; the surfaces of each pair oflocking surfaces being curved in opposite directions in transversecrosssection, at least at their edges; and clearance being providedbetween opposed non-locking surfaces of said tool parts.

5. An excavator tool part comprising a body portion and a nose portionextending from said body portion for cooperation with a further toolpart having a major external load bearing surface; said nose portionhaving a pair of locking surfaces which extend transverse to said majorload bearing surface and a pair of nonlocking surfaces which extendtransverse to said locking surfaces; the surfaces of each pair facing inopposite directions and converge in a direction away from said bodyportion; the included angle defined between said pair of lockingsurfaces being less than the included angle defined between said pair ofnondocking surfaces; and the surfaces of said pair of locking surfacesbeing curved in opposite directions in transverse crosssection, at leastat their edges. whereby said locking surfaces are engageable withsubstantially complementary surfaces of said further tool part tofrictionally retain said tool parts in combination and to restrain saidtool parts against substantial relative lateral movement.

6. An excavator tool part according to claim 5, wherein said noseportion is split longitudinally to form two spaced sections therebydefining a figure having eight side surfaces in transverse cross-sectionof said nose portion, each section including at least one of saidlocking surfaces.

7. An excavator tool part comprising a body portion having a cavitytherein for receiving a portion of a further tool part. said bodyportion having a major external load bearing surace; said cavity havinga pair of locking surfaces which extend transverse to said major loadbearing surface and a pair of non-locking surfaces which extendtransverse to said locking surfaces; the surfaces of each pair facing inopposite directions and converging in a direction away from the mouth ofsaid cavity; the included angle defined between said pair of lockingsurfaces being less than the included angle defined between said pair ofnon-locking surfaces; and the surfaces of said pair of locking surfacesbeing curved in opposite directions in transverse crosssection, at leastat their edges; whereby said locking surfaces are engageable withsubstantially complementary surfaces of said further tool part tofrictionally retain said tool parts in combination and to restrain saidtool parts against substantial relative lateral movement.

8. An excavator tool according to claim 7, member said cavity is dividedlongitudinally by a tongue membere having two lateral side surfaces toform two sections, each section including at least one of said lockingsurfaces.

9. An excavator tool according to claim 8, wherein the lateral sidesurfaces of said tongue member converge towards said mouth, each lateralside surface forming an additional locking surface.

10. An excavator tool according to claim 9, wherein said pair of lockingsurfaces of said cavity are located in opposed relationship to saidtongue member.

ll. An excavator too] including two parts held in releasablecombination; one of said parts forming a replaceable part and having amajor external load bearing surface, and the other said part forming amounting part; said mounting part comprising a body portion and a noseportion extending from said body portion; said replaceable part having acavity therein and within which said nose portion is located; said partsbeing held in combination by frictional wedging engagement betweenlocking surfaces of said nose portion and said cavity respectively. eachof said locking surfaces extending transverse to said major load bearingsurface; each part having at least one pair of said locking surfaces andat least one pair of non-locking surfaces which extend transverse tosaid locking surfaces, the surfaces of each said pair face in oppositedirections and converge in a direction away from said body portion ofthe replaceable part; the included angle defined between each pair oflocking surfaces being less than the included angle defined between eachpair of nonlocking surfaces; the surfaces of each pair of lockingsurfaces being curved in opposite directions in transversecross-section, at least at their edges; and clearance being providedbetween opposed non-locking surfaces of said tool parts.

12. An excavator tool including two parts held in releasablecombination; one of said parts forming a replaceable part and having amajor external load bearing surface. and the other said part forming amounting part; said replaceable part having a cavity therein whichreceives a portion of said mounting part; said parts being held incombination by frictional wedging engagement between locking surfaces ofsaid cavity and said portion respectively, each of said locking surfacesextending transverse to said major load bearing surface; each parthaving at least one pair of said locking surfaces and at least one pairof non-locking surfaces which extend transverse to said lockingsurfaces, the surfaces of each said pair face in opposite directions andconverge in a direction away from the open mouth of said cavity; theincluded angle defined between each pair of locking surfaces being lessthan the included angle defined between each pair of nonlockingsurfaces; the surfaces of each pair of locking surfaces being curved inopposite directions in trans verse cross-section, at least at theiredges; and clearance being provided between opposed non-locking surfacesof said tool parts.

13. An excavator tool according to claim 12, wherein said mounting partis in the form of a plate member having an edge portion thereof locatedin said cavity.

14. An excavator tool according to claim 12, wherein the included angledefined between said locking surfaces is within a range of 2 to 8inclusive and the included angle defined between said non-lockingsurfaces is within the range to 40 inclusive 15. An excavator tool partadapted for wedging engagement with another tool part and having a majorexternal load bearing surface and locking side surfaces which extendtransverse to said major load bearing surface said locking side surfacesfacing in opposite directions, being non-parallel in the direction ofengagement with said another tool part and being curved in oppositedirections in transverse cross-section, at least at their edges, andnon-locking side surfaces extending transverse to said locking surfacessaid non-locking surfaces facing in opposite directions and beingnonparallel in the direction of engagement with said another tool part,the included angle between said nonlocking surfaces is greater than theincluded angle between said locking surfaces, said included anglebetween said locking surfaces being in the range of 2 to 8 inclusive,and the included angle between said nonlocking surfaces being in therange of 20 to 40 inclusive.

16. A tool part as defined in claim 15 wherein said locking sidesurfaces are the only locking means between said tool part and saidanother tool part.

1. An excavator tool part adapted for weding engagement with anothertool and having a motor external load bearing surface and a socketincluding locking side surfaces which extend transverse to said majorload bearing surface, said locking side surfaces facing in oppositedirections, being non-parallel in the direction of engagement with saidanother tool part and being curved in opposite directions in transversecross-section, at least at their edges, and non-locking socket sidesurfaces extending transverse to said locking surfaces, said non-lockingsurfaces facing in opposite directions and being non-parallel in thedirection of engagement with said another tool part, and the includedangle between said non-locking surfaces is greater than the includedangle between said locking surfaces.
 2. A tool part as defined in claim1 wherein, the included angle between said locking surfaces is in therange 2* to 8* inclusive.
 3. A tool part according to claim 2 whereinthe included angle between said non-locking surfaces is in the range 20*to 40* inclusive.
 4. An excavator tool including two parts held inreleasable combination; one part being subjected to wear in use andbeing replaceable, and having a major external load bearing surface; onesaid part having a socket, the second part having a nose, said partsbeing held in combination by frictional wedging engagement of saidsocket and nose by respective locking surfaces, all of which extendtransverse to said major load bearing surface; each part having at leastone pair of said locking surfaces and at least one pair of non-lockingsurfaces which extend transverse to said locking surfaces, the surfacesof each pair face in opposite directions and are non-parallel in thedirection of engagement between said parts; the included angle definedbetween each pair of locking surfaces being less than the included angledefined between each pair of non-locking surfaces; the surfaces of eachpair of locking surfaces being curved in opposite directions intransverse cross-section, at least at their edges; and clearance beingprovided between opposed non-locking surfaces of said tool parts.
 5. Anexcavator tool part comprising a body portion and a nose portionextending from said body portion for cooperation with a further toolpart having a major external load bearing surface; said nose portionhaving a pair of locking surfaces which extend transverse to said majorload bearing surface and a pair of non-locking surfaces which extendtransverse to said locking surfaces; the surfaces of each pair facing inopposite directions and converge in a direction away from said bodyportion; the included angle defined between said pair of lockingsurfaces being less than the included angle defined between said pair ofnon-locking surfaces; and the surfaces of said pair of locking surfacesbeing curved in opposite directions in transverse cross-section, atleast at their edges, whereby said locking surfaces are engageable withsubstantially complementary surfaces of said further tool part tofrictionally retain said tool parts in combination and to restrain saidtool parts against substantial relative lateral movement.
 6. Anexcavator tool part according to claim 5, wherein said nose portion issplit longitudinally to form two spaced sections thereby defining afigure having eight side surfaces in transverse cross-section of saidnose portion, each section including at least one of said lockingsurfaces.
 7. An excavator tool part comprising a body portion having acavity therein for receiving a portion of a further tool part, said bodyportion having a major external load bearing surace; said cavity havinga pair of locking surfaces which extend transverse to said major loadbearing surface and a pair of non-locking surfaces which extendtransverse to said locking surfaces; the surfaces of each pair facing inopposite directions and converging in a direction away from the mouth ofsaid cavity; the included angle defined between said pair of lockingsurfaces being less than the included angle defined between said pair ofnon-locking surfaces; and the surfaces of said pair of locking surfacesbeing curved in opposite directions in transverse cross-section, atleast at their edges; whereby said locking surfaces are engageable withsubstantially complementary surfaces of said further tool part tofrictionally retain said tool parts in combination and to restrain saidtool parts against substantial relative lateral movement.
 8. Anexcavator tool according to claim 7, member said cavity is dividedlongitudinally by a tongue membere having two lateral side surfaces toform two sections, each section including at least one of said lockingsurfaces.
 9. An excavator tool according to claim 8, wherein the lateralside surfaces of said tongue member converge towards said mouth, eachlateral side surface forming an additional locking surface.
 10. Anexcavator tool according to claim 9, wherein said pair of lockingsurfaces of said cavity are located in opposed relationship to saidtongue member.
 11. An excavator tool including two parts held inreleasable combination; one of said parts forming a replaceable part andhaving a major external load bearing surface, and the other said partforming a mounting part; said mounting part comprising a body portionand a nose portion extending from said body portion; said replaceablepart having a cavity therein and within which said nose portion islocated; said parts being held in combination by frictional wedgingengagement between locking surfaces of said nose portion and said cavityrespectively, each of said locking surfaces extending transverse to saidmajor load bearing surface; each part having at least one pair of saidlocking surfaces and at least one pair of non-locking surfaces whichextend transverse to said locking surfaces, the surfaces of each saidpair face in opposite directions and converge in a direction away fromsaid body portion of the replaceable part; the included angle definedbetween each pair of locking surfaces being less than the included angledefined between each pair of non-locking surfaces; the surfaces of eachpair of locking surfaces being curved in opposite directions intransverse cross-section, at least at their edges; and clearance beingprovided between opposed non-locking surfaces of said tool parts.
 12. Anexcavator tool including two parts held in releasable combination; oneof said parts forming a replaceable part and having a major externalload bearing surface, and the other said part forming a mounting part;said replaceable part having a cavity therein which receives a portionof said mounting part; said parts being held in combination byfrictional wedging engagement between locking surfaces of said cavityand said portion respectively, each of said locking surfaces extendingtransverse to said major load bearing surface; each part having at leastone pair of said lockIng surfaces and at least one pair of non-lockingsurfaces which extend transverse to said locking surfaces, the surfacesof each said pair face in opposite directions and converge in adirection away from the open mouth of said cavity; the included angledefined between each pair of locking surfaces being less than theincluded angle defined between each pair of non-locking surfaces; thesurfaces of each pair of locking surfaces being curved in oppositedirections in transverse cross-section, at least at their edges; andclearance being provided between opposed non-locking surfaces of saidtool parts.
 13. An excavator tool according to claim 12, wherein saidmounting part is in the form of a plate member having an edge portionthereof located in said cavity.
 14. An excavator tool according to claim12, wherein the included angle defined between said locking surfaces iswithin a range of 2* to 8* inclusive and the included angle definedbetween said non-locking surfaces is within the range 20* to 40*inclusive.
 15. An excavator tool part adapted for wedging engagementwith another tool part and having a major external load bearing surfaceand locking side surfaces which extend transverse to said major loadbearing surface, said locking side surfaces facing in oppositedirections, being non-parallel in the direction of engagement with saidanother tool part and being curved in opposite directions in transversecross-section, at least at their edges, and non-locking side surfacesextending transverse to said locking surfaces, said non-locking surfacesfacing in opposite directions and being non-parallel in the direction ofengagement with said another tool part, the included angle between saidnon-locking surfaces is greater than the included angle between saidlocking surfaces, said included angle between said locking surfacesbeing in the range of 2* to 8* inclusive, and the included angle betweensaid non-locking surfaces being in the range of 20* to 40* inclusive.16. A tool part as defined in claim 15 wherein said locking sidesurfaces are the only locking means between said tool part and saidanother tool part.